Table 2. Summary of TCE studies using a bladder pump.
Whole system
(pump + tubing)
Bladder pump only
Tubing only
Mean initial conc.
Volumes of
Mean desorbed conc.
Mean desorbed conc.
Mean desorbed conc.
(mg/L)† (S.D.)
(mg/L)† (S.D.)
(mg/L)† (S.D.)
TCE study
(mg/L)* (S.D.)
Treatment
DI rinse
Third
136 (1)
none
3
0.524
(0.003)
wash
3
0.010
(0.001)
6
0.010
(0.002)
9
0.026
(0.002)
wash + one week
0.053 (0.002)
0.011 (0.005)
storage
Fourth
0.0156 (0.0008)
none
3
0.0039 (0.001)
wash
3
LD
Fifth
152 (3)
EPA wash
1
0.034 (0.002)
3
0.015 (0.002)
6
0.026 (0.001)
Sixth
130 (1)
hot air drying
1
0.183 (0.040)
0.0043
(0.0013)
3
LD
0.0046
(0.0010)
6
LD
0.0057
(0.0006)
9
LD
0.005
(0.001)
*
Concentration of the well water
†
Concentration found in DI water from the "decontaminated" device
LD = Less than method detection limit (0.0024 mg/L)
S.D. = Standard deviation
phase I of these studies (Parker and Ranney 1997b)
week was not sufficient to remove this contami-
have shown that permeable polymeric materials,
nation.
such as PTFE, that had sorbed VOCs required hot
Fourth TCE study--Effect of wash procedure on
air drying (105C) in addition to a hot detergent
pump exposed to low concentrations. When the same
wash and a hot water rinse.
wash procedure was used to clean a different
Sixth TCE study--Effect of a wash and oven drying
pump system that had been exposed to relatively
on a pump exposed to high concentrations. In this
low concentrations of TCE, decontamination was
study, we used the same wash procedure as the
effective (Table 2). We anticipated that desorbed
previous experiment and then pumped hot air
TCE concentrations would be below the detection
(70C) through the pump and sampling tubing
limit given the very low initial concentration of
line, each individually. We selected a lower tem-
TCE in the well, and that the previous study
perature, 70C, for this study because of problems
showed that this washing procedure yielded 3-
we had experienced with the bailer warping at
and 4-log reductions in desorbed TCE concentra-
the higher temperature (105C). By running DI
tions.
water through the pump and tubing separately,
Fifth TCE study--Effect of EPA washing protocol
we see that we were able to completely decon-
on pump exposed to high concentrations. Because the
taminate the pump itself but not the tubing (Table
previous wash procedure was not effective in re-
A6). Desorbed concentrations from the tubing
moving all the contamination from the sampling
were approximately the same as the EPA's maxi-
pump that had been exposed to high concentra-
mum contamination level (MCL) of 0.005 mg/L
tions of TCE, we tested a second washing proce-
and well above the EPA's maximum contaminant
dure outlined by the US EPA Region I (1996). The
level goal (MCLG) of zero (US EPA 1994).
pump was exposed to high concentrations of TCE
for one week. However, again we see that there
Pesticide study
was detectable residual contamination in the DI
Initial concentrations of two of the pesticides,
water that was pumped through the decontami-
heptachlor and aldrin, were significantly lower in
nated system (Table 2).
samples taken with the bladder pump than those
The results from this study and the third study
taken with the bailer (Table A7). We believe this
are not unexpected given that our findings in
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